Influence of the substitution pattern (ortho vs para) on the structure and luminescence of silver(I) complexes ligated by diphenylphosphinobenzoic acids

Abstract

The reaction of AgCF3SO3 with diphenylphosphinobenzoic acids leads to a cyclic dinuclear or a polynuclear silver(I) compound, depending on the relative position of phosphine versus carboxylic functional group. The dimers [Ag2(OSO2CF3)2(μ-O,P-PPh2C6H4COOH-o)2] 1 or [{Ag(μ-O,P-PPh2C6H4COOH-o)(OH2)2}2](CF3SO3)2·2CH2Cl21a are 12-membered diargentacycles with a silver–silver distance of 3.982 or 3.754 Å, while the polymer [Agn(OSO2CF3)n(μ-O,P-PPh2C6H4COOH-p)n] 2 is a 1D type. The ligand is always acting as non-chelating bridge, being the silver center coordinated to the phosphine phosphorous, and one oxygen (carbonyl) of the carboxylic acid of next fragment. One oxygen of the triflate anion or two water molecules complete the coordination sphere. Besides, p-(diphenylphosphino)benzoic acid compound is emissive in solution and in the solid state at 298 and 77 K, while compound with the ortho ligand is not. At 298 K, the emissions are centered at 471 nm in the solid state and at 416 nm in solution.